where \({T(\mathrm {k})}\)  is the transfer function, \(n_{s}\)  is the scalar spectral index of the primordial fluctuation spectrum, \(\mathrm {k}\)  is the wavenumber and
\(\delta _{H}\)  is defined [1]}, [2]} by
\(\delta _{H}\approx 1.94\times 10^{-5}\mathrm {\Omega _{M,0}}^{-0.785-0.05\mathrm {\ln \Omega _{M,0}}}e^{-0.95(n_{s}-1)}.\,\,\) 
